Closing device consisting of a plastic material

ABSTRACT

The invention relates to a closing device consisting of a lower part ( 2 ) with a cylindrical outlet and a flange ( 3 ), said device being closable by a screw cap ( 4 ). When the container is first opened, means in the screw cap act on a perforating element ( 5 ) mounted in the lower part. Said perforating element ( 5 ) is open on both sides and has at least one cutting tooth ( 7 ) and a deflector ( 10 ). Both act on a container consisting only of a plastic film. The deflector ( 10 ) tightens the film to be perforated and cut. The deflector ( 10 ) is the same height as the at least one cutting tooth ( 7 ) or protrudes past same.

BACKGROUND OF THE INVENTION

The present invention relates to a closing device consisting of a plastic material for applying to a closed container consisting of a plastic film material, wherein said closing device comprises a lower part with a cylindrical outlet and a flange for attaching same to the container and a screw cap which is screwably fixed to the lower part. Said closing device further comprises a cylindrical perforating element, which is open to both sides in the axial direction and travels in a threaded section of the outlet of said lower part, wherein means are located in the screw cap, which move the perforating element downwards in a helical manner when said screw cap is first turned and wherein said cylindrical perforating element has at least one tooth and a deflector on the cylindrical wall thereof at the end which is directed towards the container wall.

Closing devices of the type previously mentioned have to date only been mounted on containers produced from laminated film material. These laminated films comprise at least three layers of different types of material. Such a film consists on the one hand of a cardboard layer, which provides the container with the necessary rigidity, an aluminum layer serving as an aroma barrier and a plastic layer which ensures the required denseness. In order to separate these three layers, the corresponding perforating element of the aforementioned closing device must fulfill various functions. A plurality of saw teeth are often recommended for separating the cardboard layer, wherein a raised tooth cuts through the aluminum layer with a forward cutting edge and wherein a perforating tooth breaks through the plastic layer before the aforementioned cutting edge can continue to cut the plastic film. In the case of these containers consisting of laminated film material, the separation of the cardboard material generally represents a problem. Particularly if the partial press cut, which serves as a support and at least separates the cardboard layer to some extent, does not exactly correspond to the cutting line of the perforating element, the teeth are then either too weak or in the case of a considerable number of teeth, the cardboard material comes between the teeth and said teeth can thereafter hardly produce a perforating effect.

SUMMARY OF THE INVENTION

The present invention relates, however, to a closing device, which is applied to a pure plastic film material. Such tubular bags, mostly referred to as pouches in the technical language, have not been opened to date by means of the aforementioned closing devices. On the contrary, an opening was already punched out and a closure including the outlet thereof was welded on the pouches so as to be correctly positioned or was shrink-wrapped between two film layers. Because the shelf-life of the filled food material or beverage is thereby solely dependent upon the impermeability of the closure, such closures were virtually used only in unproblematic areas, particularly in the area of cosmetics. When using a closing device of the kind mentioned at the beginning of the application, the container pouch remains completely closed until the point of first being opened. An increased shelf-life is thereby provided. In addition, the plastic film in such applications according to the invention is substantially more robust and is designed having a greater wall thickness than the very thin plastic film layer in the case of a laminated film. This in turn gives rise to other demands being placed on the closing device. Initial trials with closing devices from prior art did not produce any reliable results. Plastic films tend to deform to a substantially greater extent. When using closing devices from prior art, the cutting teeth got caught in the film with the perforating tooth thereof and said film was thereby stretched. As a result of such stretching, the molecules are straightened out in thin plastic films and the material thereby becomes substantially tougher. It has basically been determined that plastic films of the kind of interest here tear easily or can be pierced or cut; however, the actual penetration of the film by the teeth can present a problem. The corresponding cardboard layer, which holds the plastic film in an immovable position, is particularly lacking in this case. The better the film is pre-tightened, the better said film can be perforated and subsequently cut open.

A closing device of the type mentioned at the beginning of the application is known from the WIPO patent publication WO 2008/092289. Said closing device has a plurality of cutting teeth evenly distributed across the circumference thereof, and the perforating element additionally comprises a deflector, the height of which is less than the height of the teeth. Said deflector consequently serves merely to push the partially cut-out rondelle out of the region of the outlet and to hold said rondelle in this deflected position in order to ensure that said rondelle, which has been turned down to the side, is held outside of the outlet region. The invention does not provide for an additional function of said deflector nor is one conceivable.

In contrast thereto, a closing device of similar type for a container consisting of laminated paper or cardboard is further known from the WIPO patent publication WO 2004/083055, which again comprises a deflector that is not as high as the at least one cutting tooth. Said deflector is additionally equipped with a perforating tooth. The corresponding inventive idea is based on the fact that in the event that the plastic film layer is not pierced by at least one cutting tooth, the film is tightened and pressed downwards and the succeeding deflector comprising a perforating tooth would be able to pierce the tightened film. This solution is based, however, on the fact that the plastic film layer of the laminated paper or cardboard, which is fixedly connected thereto, basically does not give way. Thus, if the previous teeth have already partially penetrated the laminated paper or cardboard wall, the unseparated layer continues to extend approximately at the original height. If the container consists, however, of a pure plastic film, the elasticity is therefore substantially greater and the entire layer is thus substantially more stretched and tightened, whereby the strength and toughness of the plastic film is increased and at the same time the perforating tooth of the deflector does not or hardly comes in contact with the downwardly deformed film region. Said solution can thus not be used in the case of a plastic container consisting of pure plastic film.

It is therefore the aim of the present invention to improve a closing device of the kind mentioned at the beginning of the application such that said device is suited to close a container consisting of pure plastic film and containing no proportion of paper or cardboard, wherein an improved and reliable opening of the container is achieved.

This aim is met by a closing device, which is characterized by the deflector protruding at least approximately past the at least one tooth so that during the initial opening of the container, said deflector contacts the container wall, which is to be cut open, simultaneously with or prior to the at least one cutting tooth coming in contact with same. In so doing, a certain pre-tightening of the plastic film is achieved prior to said cutting tooth contacting said film; thus enabling said cutting tooth with the perforating tip thereof to pierce said film in the tightened state and subsequently to cut the same.

BRIEF DESCRIPTION OF THE DRAWING

A preferred exemplary embodiment of the subject matter of the invention is depicted in the accompanying drawings and subsequently described. The following is shown:

FIGS. 1-4 a closing device according to the invention on its own in a state, wherein said device is not mounted on a container and is shown in different opening positions, in which the cap is unscrewed to varying degrees and the deflector correspondingly projects to varying degrees out of the cylindrical outlet.

FIG. 5 a development drawing of the deflector according to the invention.

DETAILED DESCRIPTION

As previously mentioned, FIGS. 1 to 4 show the closing device according to the invention in different opening positions. In the assembled end position prior to said closing device being welded onto the corresponding container, the perforating element 5 of interest here is situated completely within the lower part 2, of which, as shown in FIG. 1, practically only a flange 3 is visible. Said closing device 1 consists of three parts, namely the lower part 2, a screw cap 4, which is screwed onto said lower part 2, and a cylindrical perforating element which in the assembled state lies completely in a cylindrical outlet 6, which is a part of the lower part 2.

The cylindrical perforating element 5 has an external thread, which meshes with an internal thread of the previously mentioned outlet 6. In so doing, said perforating element 5 is driven by means in the screw cap 4, which are not depicted here and also are not relevant for understanding the invention. These means are normally driving elements, which stay in contact with corresponding driving elements on the inside of the cylindrical perforating element 5. During the initial opening of the closing device 1, the screw cap 4 is unscrewed, wherein said cap is moved away in the direction of the flange 3 and consequently also in the direction of the wall of the container, upon which the closing device 1 is mounted. At the same time, the cylindrical perforating element 5, which has the same rotational direction but an opposite axial component, is moved so that said perforating element 5 moves out of the outlet 6; and in the process the wall of the container, which is not depicted here, is opened.

As mentioned earlier, the initial position is shown in FIG. 1, in that the cylindrical perforating element 5 as well as the teeth thereof or respectively at least one tooth 7 thereof as well as the deflector 10 thereof completely lie within the outlet 6. In FIG. 2, the screw cap 4 is partially screwed off and the perforating element 5 protrudes with the teeth 7 thereof and the deflector 10 beyond the flange 3 of the lower part 2. That position is shown in FIGS. 3 and 4, in which the cylindrical perforating element is maximally screwed out of said lower part 2, wherein said element is still being held in said lower part 2 or respectively in the outlet 6 thereof. In this position, the container wall is, however, completely cut open. When the closing device is closed again, the screw cap 4 is screwed on by way of the driving elements of said screw cap, which no longer come into operative connection with the driving element of the perforating element.

A developed view of the perforating element 5 is shown in enlarged scale in FIG. 5. In this case, the inner surface of said perforating element can be seen. Said perforating element 5 has a cylindrical wall 15, the edge 16 of which that faces the cap runs in a straight line, while the teeth 7 and the deflector 10 are integrally formed on the edge facing the container. Said teeth 7 have a perforating tip 8 which defines the maximum height as well as an inclined cutting edge 9. The border of the tooth 7 runs in an arch from the perforating tip 8 along the side which is remote from the cutting edge 9 to the edge 17. The driving element 11 previously mentioned is integrally formed at least in the region of one of the cutting teeth 7. The aforementioned deflector 10 is disposed in the direction of rotation D and in succession to the two teeth 7. Said deflector 10 comprises a shoulder 13 which precedes in the direction of rotation D and is disposed so as to project above the aforementioned edge 17 at least by half of the height of a cutting tooth 7 from the aforementioned edge 17. The shoulder 13 comprises accordingly an upper shoulder edge 18. A rounded edge 14, which forms a superelevation 12, succeeds said shoulder edge 18 so as to protrude above the same. This superelevation extends at least to the same height of the at least one cutting tooth 7. This superelevation can, however, also be higher and this difference in height, i.e. the distance protruding above the at least one cutting tooth, is denoted by the annotation Δh. This difference Δh can be between 0 and 15% of the diameter of the perforating element 5.

Due to the rounded edge 14, said edge cannot get caught in the plastic film and merely presses against the same, whereby said edge simultaneously tightens said plastic film. In so doing, an improved perforation and an improved perforation effect are achieved, and at the same time the cutting edge 9 now operates smoothly. Were the superelevation designed too high, the film would be deformed so far in a downward direction that the cutting teeth subsequently acting on said film would no longer come into contact with the same. It is therefore sufficient if the superelevation is at least the same height as the perforating tip of the at least one cutting tooth 7 or slightly protrudes above the height of said tooth.

The forces arising here are generally relatively large, even on the deflector 10; and there is a risk that this elevated section will be bent. By means of its three dimensional, round form, the forerunning shoulder 13 has a stiffening effect, whereas the part actually having an effect on the force, namely the rounded edge, protrudes only slightly beyond the shoulder edge 18. 

1. A closing device (1) made of a plastic material for applying to a closed container made of plastic film material, the closing device comprising a lower part (2) with a cylindrical outlet (6) and a flange (3) for attaching said device to the container and a screw cap (4) which is screwably fixed to the lower part (2) as well as a cylindrical perforating element (5), which is open to both sides in an axial direction and travels in a threaded section of the outlet (6) of said lower part (2), wherein means are located in the screw cap (4), which move the perforating element (5) downwards in a helical manner when said screw cap (4) is initially unscrewed and wherein said cylindrical perforating element (5) has at least one cutting tooth (7) and a deflector (10) on a cylindrical wall thereof at an end which in the assembled state is directed towards a container wall, characterized in that the deflector (10) protrudes approximately past the at least one cutting tooth (7) so that during the initial opening of the container, said deflector contacts the container wall, which is to be cut open, simultaneously with or prior to said at least one cutting tooth (7) coming in contact with said container wall.
 2. The closing device according to claim 1, characterized in that the difference in height between a highest point of the deflector (10) and a highest cutting tooth (7) Δh is between 0.0% and 15% of a diameter of the cylindrical perforating element (5).
 3. The closing device according to claim 1, characterized in that the deflector (10) has a rounded edge, which is directed towards the container wall and runs in a curved fashion in the direction of extension thereof.
 4. The closing device according to claim 3, characterized in that the deflector (10) has a rectangular shape in a developed view, one edge of which is integrally formed on a bottom edge of the perforating element (5), while the rounded edge (14) lying opposite to said bottom edge is curved in the direction of extension in such a way that a maximum cant lies centrally between lateral edges.
 5. The closing device according to claim 3, characterized in that the rounded edge (14) forms a circular-arc section in the developed view.
 6. The closing device according to claim 3, characterized in that the deflector (10) comprises a stiffening shoulder, which during opening precedes the rounded edge in the direction of rotation, and said rounded edge protrudes past the shoulder by more than the amount Δh.
 7. The closing device according to claim 1, characterized in that the perforating element (5) comprises two cutting teeth (7), tips of which as well as a highest point of the deflector (10) are evenly distributed over a circumference of said perforating element (5). 